Winx Club Forever
Alfea's Greenhouse is where many species of magical plants are grown at Alfea, possibly for use in magic classes or in potion-making. Eldora used to teach magical botany there but after she left the school it was abandoned and became a secret location. Professor Palladium knew about it's location, and presumably so did other teachers at Alfea. After the Winx discovers this place, Flora became its caretaker.
The Secret Greenhouse appears to be covered by a large, stainless glass dome. Inside the greenhouse are various breeds of plants, many of which span from flowers, flytraps, vines, and many others.
Eldora used to teach magical botany there but after she left the school it was abandoned and became a secret location. It is believed that not just anyone can enter the greenhouse without special permission.
Season 6In "The Secret Greenhouse", Palladium informs the Winx Club about the greenhouse formerlly hosted by Eldora, the Fairy Godmother. The Winx, along with Selina, go to the greenhouse to track clues on Eldora's whereabouts. Flora then pulls out Eldora's favorite flower, where Bloom asks if Selina recognizes it. She replies she doesn't but the answer could be found in the greenhouse. They all split up to find a matching flower. While the Winx were looking about, Selina curses a batch of roses. Once Flora goes to smell the batch, she immediately collapses. Bloom is shocked to find out she had been poisoned, Bloom didn't know what to do as the only one who could counteract floral poisons is Flora. Selina asks if there's a potions lab in the greenhouse, and Stella asks how she would even know what to do. She replies she learned floral magic from Eldora, so she would know how to counteract it. Bloom takes Selina with her to find the potions lab. Aisha suggests going to get Palladium in the meantime. When no one was looking, Selina secretly curses a set of plants turning them into huge plant monsters that attack Stella, Musa, Tecna, and Aisha, trapping them in the greenhouse. The four transform to fight the plant monsters and protect the incapacitated Flora.
Stella, Musa, Tecna, and Aisha continue to fight off the plant monsters until Bloom arrives. They tell her to go help Flora while they deal with them. Bloom comes down and was about to give the potion to Flora, until it was shot out of her hand by Helia, much to her confusion. She looks up to see the Specialists, Paladins, and Palladium in the greenhouse. Sky tells Bloom that the potion she almost gave Flora was no antidote. Bloom was confused as to how since it was given to her by Selina, and Palladium points out that it was actually a poison. She became horrified realizing she had come close to accidentally killing Flora. Palladium quickly gives Flora a real antidote. As the guys assist the other girls in staving off the plant monsters, Flora recovers, gets up and reverts them back to normal. All cheer at the victory, but Flora noticed Bloom feeling traumatized.In "Broken Dreams", Flora returns to the secret greenhouse to keep looking for clues on Eldora's location. Many of the plans communicate to Flora, but not many know about the type of flower Flora possesses. However, a red leaved flower, Tendril, informs Flora that it is a flower grown in Gardenia! Flora is reminded of what Lu Wei told the Winx: that Eldora resorted to living where her favorite flower grew. In excitement about Eldora's location, the Winx travel back to Gardenia, to Bloom's aide especially.
Later, it was seen again in "The Curse of Fearwood", when Flora brings Helia to the Secret Greenhouse to show him the wonderful plants the room contains, Helia is a bit hesitant to go in afraid that they might get into trouble, but Flora reassures him and tells him she is now the caretaker. When they go inside Helia is speechless at the sight of the Greenhouse and Flora reveals that she brought back some of the Grabbing Vines from the Caribbean mission. While admiring them a group of students come in asking Flora for the scheduled tour she was supposed to give. She leaves, but not before asking Helia to tend to the vines while she goes off to do her duty. Helia didn't quite get the instruction on how to properly tend the plant and winds up getting entangled by it, much to the students shock. Flora is able to calm the plants and gets Helia down, Flora tells him he didn't do it right as he needs to be very careful around these kinds of plants. Helia, feeling that Flora is disappointed in him leaves the room, despite Flora's protest, and accidentally bumps into Musa along the way.